CVE-2026-72809

HIGHPre-NVD 8.08.0—
EchelonGraph scoreHIGH confidence

Score 8.0 from GitHub Security Advisory (severity: HIGH) published 2026-08-12. a secondary CVSS source baseline 8.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
8.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.0Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

SiYuan versions <= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel's CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including /api/system/exit, getNetwork, getWorkspaceInfo, /assets/*, and /export/*). These localhost bypasses sit outside the access auth code gate, so they apply even when an access auth code is configured. Because the fixed-port reverse proxy forwards requests to the kernel over loopback without injecting an authentication token and does not configure trusted proxies, a request forwarded through this proxy reaches the kernel with RemoteAddr = 127.0.0.1. If the fixed-port proxy is bound to a network interface, this could allow a remote unauthenticated attacker to obtain admin access on the affected endpoints; however, per the advisory this remote forwarding behavior was established only by code inspection and was not reproduced end-to-end.

CVSS v3
8.0
EG Score
8.0(high)
EG Risk
52(Track)
EG Risk 52/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity80% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

August 12, 2026

Last Modified

August 14, 2026

Advisory Details (2)

Auto-updated Aug 12, 2026
No patch confirmed yet.
generic

SiYuan before v3.7.4 Authentication Bypass via Localhost Trust | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust
github Patch Available🟡 PoC Available

Localhost-trust admin bypass on auth-code-gated endpoints, with potential remote reachability via the fixed-port proxy (needs maintainer confirmation) · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9

Vendor Advisories for CVE-2026-72809(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 34× in last 7d / 41× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-21 08:53 UTCGHSA enrichment
  2. 2026-08-20 20:06 UTCGHSA enrichment
  3. 2026-08-20 07:21 UTCGHSA enrichment
  4. 2026-08-19 18:36 UTCEG score recompute
  5. 2026-08-19 18:36 UTCGHSA enrichment
  6. 2026-08-19 17:04 UTCEPSS rescore
  7. 2026-08-19 04:23 UTCGHSA enrichment
  8. 2026-08-18 15:37 UTCEG score recompute
  9. 2026-08-18 15:36 UTCGHSA enrichment
  10. 2026-08-18 13:49 UTCEPSS rescore
  11. 2026-08-18 13:49 UTCEPSS rescore
  12. 2026-08-18 02:47 UTCGHSA enrichment
  13. 2026-08-17 14:02 UTCEG score recompute
  14. 2026-08-17 14:02 UTCGHSA enrichment
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-17 01:18 UTCEG score recompute
  17. 2026-08-17 01:18 UTCGHSA enrichment
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 12:33 UTCEG score recompute
  21. 2026-08-16 12:33 UTCGHSA enrichment
  22. 2026-08-16 02:15 UTCEPSS rescore
  23. 2026-08-15 23:48 UTCGHSA enrichment
  24. 2026-08-15 11:03 UTCEG score recompute
  25. 2026-08-15 11:03 UTCGHSA enrichment
Show 16 more
  1. 2026-08-15 01:31 UTCEPSS rescore
  2. 2026-08-14 22:18 UTCEG score recompute
  3. 2026-08-14 22:18 UTCGHSA enrichment
  4. 2026-08-14 22:14 UTCEG score recompute
  5. 2026-08-14 22:14 UTCGHSA enrichment
  6. 2026-08-14 17:08 UTCEG score recompute
  7. 2026-08-14 17:08 UTCGHSA enrichment
  8. 2026-08-14 10:34 UTCEG score recompute
  9. 2026-08-14 10:34 UTCGHSA enrichment
  10. 2026-08-13 22:00 UTCEPSS rescore
  11. 2026-08-13 21:49 UTCGHSA enrichment
  12. 2026-08-13 09:04 UTCEG score recompute
  13. 2026-08-13 09:04 UTCGHSA enrichment
  14. 2026-08-12 20:20 UTCEG score recompute
  15. 2026-08-12 19:21 UTCEG score recompute
  16. 2026-08-12 19:20 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-72809?
CVE-2026-72809 is a high vulnerability published on August 12, 2026. SiYuan versions <= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel's CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including…
When was CVE-2026-72809 disclosed?
CVE-2026-72809 was first published in the National Vulnerability Database on August 12, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-72809 actively exploited?
CVE-2026-72809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 89.0% of all scored CVEs.
What is the CVSS score of CVE-2026-72809?
CVE-2026-72809 has a CVSS v3 base score of 8.0 (NVD).
How do I remediate CVE-2026-72809?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-72809, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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